Tally Ho

Here's the secenario. 2005 convertible with 80K miles, non Z51, new Michelin tires. At around 80mph the front end gets real light and starts to wander like the car is steering itself. It also gets intermittent active handling errors. A search here came up with a steering wheel sensor issue. Has anyone had similar issues and how did you fix it? Thanks.

Bill Curlee

First:,,,,,,,,,, Are you getting any Service Active Handling Messages in the DIC?

Second:,,, When was the last time you had a four wheel alignment and did the shop properly center the steering wheel?? Is your steering wheel nats *** centered when your driving down a straight level highway?

Do you have any EBTCM or BCM Diagnostic Trouble Codes (DTCs)


BC

Boomer111

My 08 wondered and felt light with a poor alignment. Zero camber was the culprit.

Not sure with your situation with the codes and all.

Tally Ho

More info.

No codes on the code reader.

The DIC message comes up on initial start and when first moved. Clears and does not return.

Four wheel alignment not done recently.

The steering wheel is off centre to the left.

This is not my car. I'm helping a friend in troubleshooting.

Thanks for the inputs so far.

KRAYZ308

I hade the same problem. The cure was to reset the rear toe. Unlike the front, the rear should be slightly (1-2 MM) towed out. Excessive rear toe and particularly toe in on the rear causes high speed stability issues on any chassis.

Gearhead Jim

Really?
On the last alignment, I got a little toe-IN at the rear of our 2009 Z51 Coupe, and it seems to make the car more steady on the highway.

At one time, it had some toe-out back there and was rather twitchy.

Where are the suspension experts?

SteveDoten

we hang out in the roadracing section

I've got a Snap-On laser alignment rack here in CT along with a Nascar crew chief if anyone needs an alignment or suspension setup.

Longacre scales ready to go for corner balancing also.

Gearhead Jim

Steve-

What do you think; will toe-OUT at the rear make the car more stable at speed?

TMyers

If active handling is truly coming on by itself because of a bad sensor it would cause the car to behave badly. But you would have code that could be read by just about any shop.

For an alignment zero toe up front with slight toe in on the rear will get you down the street. You can also go slight up front but you tire wear will be faster.

I run max caster, zero toe and -1.6 camber up front. On the rear I run -.01 toe and -1.1 camber. I get about 35k out of my street tires and the car is very stable at all speeds.

el es tu

Check out the spring pads then check the shocks.

I had an issue with stability in my '07 - started at 75 mph... at 135+ it felt horrible like you were driving a sedan with sloppy suspension. When I went to have some suspension upgrades done, it was found that one of the spring pads was missing and also the original shocks seemed to be at the end of their lifecycle.




EDIT: Almost forgot check all the balljoints and tierods for play

You are 100% correct. Toe in adds stability on the rear. More toe out on the rear makes it want to get loose.

On the front you want 0 to a little bit of toe out. 0 toe up front for straight line stability, but a bit of toe out will increase turn in - its a matter of preference. Too much toe out up front makes the car twitchy at speed, but makes it turn in like crazy. I run a lot of toe out to compensate for the understeer my fwd daily driver exhibits when driven hard, but it can be a handful on the highway - especially in its wanting to follow grooves in the surface. On a rwd car front toe out needs to be done conservatively.

For toe on a C6 running street tires Id suggest using 0.0 degrees up front, and 0.0 to -0.05 degrees in the rear.

C6 factory alignment specs:


Pfadt Alignment recommendations - note that the factory camber adjustment plates will probably only get you -1.2 to -1.5 degrees max camber. With aftermarket camber plates you can go much higher.